Matching DSL data link layer protocol detection

ABSTRACT

An arrangement is provided for detecting a matching DSL data link layer protocol. A matching-protocol detection mechanism is triggered under certain condition. The matching-protocol detection mechanism, once triggered, detects a matching protocol from at least one initiating protocol. The matching protocol is supported by both a customer premise equipment and a digital subscriber line access module and is used by both to establish a DSL connection. When the matching protocol is successfully identified, it is activated. When the matching protocol is not found, a failure is reported.

RELATED CASES

The present patent application is a Continuation of application Ser. No.09/861,895, filed May 22, 2001 now U.S. Pat. No. 7,006,452.

RESERVATION OF COPYRIGHT

This patent document contains information subject to copyrightprotection. The copyright owner has no objection to the facsimilereproduction by anyone of the patent document or the patent, as itappears in the U.S. Patent and Trademark Office files or records butotherwise reserves all copyright rights whatsoever.

BACKGROUND

Aspects of the present invention relate to Digital Subscriber Line(DSL). Other aspects of the present invention relate to establishing aDSL connection.

In today's highly competitive telecommunication market, new serviceswith varying levels of grades are offered everyday. Alternatives to theconventional telephony include Internet services with narrow band orbroad band options. Digital Subscriber Line (DSL) provides analternative to broadband Internet services using conventional telephonelines.

To received DSL service, a customer premise equipment (CPE) must beinstalled at a user's premise. Through the CPE, the user can establish aDSL connection with a central office via a DSL Access Module (DSLAM)installed at the central office. The CPE at the user's site and theDSLAM at the central office establish a DSL connection by communicatingwith each other via a DSL data link layer protocol. Examples of such aprotocol include High-level Data Link Control (HDLC, InternationalOrganization for Standardization, ISO/IEC 3309:1993(E)), AsynchronousTransfer Mode layer specification (ATM cell, InternationalTelecommunication Union, ITU-T Recommendation I.361 (02/99)-B-ISDN ATMLayer Specification, located athttp://www.itu.int/itudoc/itu-t/rec/i/s_i361.htm), Asynchronous TransferMode Forum, and Frame-based User-Network Interface (ATM FUNI, The ATMForum Technical Committee, defined in Frame Based User-To-NetworkInterface Specification v2.0, AF-SAA-0088.000, July 1997, located atftp://ftp.atmforum.com/pub/approved-specs/af-saa-0088.000.pdf). MostDSLAM vendors support more than one DSL data link layer protocols.

The DSL data link layer protocol used between a particular CPE and aDSLAM is usually defined via DSL data link layer protocol provisioningwhen a user initially subscribes the service. Once a DSL data link layerprotocol is chosen to facilitate the communication between a particularCPE and the DSLAM, it is used whenever a DSL connection needs to beestablished. That is, when the user associated with the CPE requests DSLservice, the CPE and the DSLAM rely on the DSL data link layer protocolagreed during the DSL data link layer protocol provisioning tofacilitate the requested service.

One problem associated with this pattern of operation is that a mismatchin DSL data link layer protocol may occur between the CPE and the DSLAM.The mismatch may be due to different reasons. For example, it may becaused by a simple configuration error at the central office. Themismatch may also occur when either the DSLAM at the central office orthe CPE at user's site is upgraded (e.g., to support more advanced DSLdata link layer protocols). When a mismatch occurs, the DSL connectioncan not be established because the CPE and the DSLAM will not be able tocommunicate. In this case, the service is not delivered and overallservice quality degrades.

Available solution to this problem is to perform a manualtrial-and-error trouble-shooting on all possible DSL data link layerprotocols until successful link synchronization is achieved. Such amanual solution is, although technologically trivial, time consuming andcostly.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described in terms of exemplaryembodiments which will be described in detail with reference to thedrawings. These embodiments are non-limiting exemplary embodiments, inwhich like reference numerals represent similar parts throughout theseveral views of the drawings, and wherein:

FIG. 1 is a high level system architecture of one embodiment of thepresent invention, in which a DSL data link layer protocol is detectedby a matching-protocol detection mechanism in a customer premiseequipment;

FIG. 2 is a high level system architecture of another embodiment of thepresent invention, in which a DSL data link layer protocol is detectedby a matching-protocol detection mechanism in a DSL access module;

FIG. 3 is a high level system architecture of yet another embodiment ofthe present invention, in which a DSL data link layer protocol isdetected by a stand-alone matching-protocol detection mechanism;

FIG. 4 depicts the internal structure of a matching-protocol detectionmechanism and its relationship with an initiating protocol list;

FIG. 5 is an example flowchart of a process, in which a matching DSLdata link layer protocol is detected;

FIG. 6 is an example flowchart of a triggering mechanism that activatesa matching-protocol detection mechanism;

FIG. 7 is an example flowchart of a process, in which a matchingprotocol is detected; and

FIG. 8 is an example flowchart of a process, in which a detectedmatching protocol is activated.

DETAILED DESCRIPTION

The invention is described below, with reference to detailedillustrative embodiments. It will be apparent that the invention can beembodied in a wide variety of forms, some of which may be quitedifferent from those of the disclosed embodiments. Consequently, thespecific structural and functional details disclosed herein are merelyrepresentative and do not limit the scope of the invention.

The processing described below may be performed by a general-purposecomputer alone or in connection with a special purpose computer. Suchprocessing may be performed by a single platform or by a distributedprocessing platform. In addition, such processing and functionality canbe implemented in the form of special purpose hardware or in the form ofsoftware being run by a general-purpose computer. Any data handled insuch processing or created as a result of such processing can be storedin any memory as is conventional in the art. By way of example, suchdata may be stored in a temporary memory, such as in the RAM of a givencomputer system or subsystem. In addition, or in the alternative, suchdata may be stored in longer-term storage devices, for example, magneticdisks, rewritable optical disks, and so on. For purposes of thedisclosure herein, a computer-readable media may comprise any form ofdata storage mechanism, including such existing memory technologies aswell as hardware or circuit representations of such structures and ofsuch data.

The inventions described herein address establishing a DSL connectionusing a DSL data link layer protocolDSL data link layer protocolsupported on both ends of the connection. FIGS. 1 to 4 show the highlevel system configurations of different and exemplary embodiments ofthe present invention, in which the DSL data link layer protocolDSL datalink layer protocol used to establish a DSL connection is selectedautomatically through a matching-protocol detection mechanism.

FIG. 1 is a high level system architecture of one embodiment of thepresent invention, in which a DSL data link layer protocolDSL data linklayer protocol is detected by a matching-protocol detection mechanismrunning on a Customer Premise Equipment (CPE). In FIG. 1, a systemconfiguration 100 comprises a Customer Premise Equipment (CPE) 110, afirst protocol list 120 stored in the CPE 110, representing all theprotocols supported by the CPE 110, a matching-protocol detectionmechanism 150, running on the CPE 110 and accessing the first protocollist 120, and a Digital Subscriber Line Access Module (DSLAM) 130 thatmay support multiple DSL data link layer protocolDSL data link layerprotocols.

A DSL connection between a user (not shown in FIG. 1) and a centraloffice (not shown in FIG. 1) may be established via the CPE 110 and theDSLAM 130. The user is connected to the CPE 110 and the DSLAM 130 isconnected to the central office and may be physically located in thecentral office. To establish a DSL connection between a user and acentral office, the CPE 110 and the DSLAM 130 communicates using certainprotocol. Both the CPE 110 and the DSLAM 130 may support a plurality ofDSL data link layer protocolDSL data link layer protocols. At any runtime, an appropriate DSL data link layer protocolDSL data link layerprotocol among a plurality of protocols supported by both the CPE 110and the DSLMA 130 may be chosen as the DSL data link layer protocolDSLdata link layer protocol to facilitate the communication between the CPE110 and the DSLAM 130.

In the system 100, the first protocol list 120 records a plurality of Nprotocols supported by the CPE 110 and is stored in the CPE 110. Forexample, the first protocol list 120 may include Asynchronous TransferMode layer specification or ATM cell, ATM Frame-based User-NetworkInterface (FUNI), or High-level Data Link Control (HDLC). Each of theprotocols in the first protocol list 120 may be listed in an individualposition in the list that can be referenced using an index value. Forexample, the first protocol listed may be stored in a position indexedas P[1], the second protocol may be stored in P[2], etc. In the system100, to establish a DSL connection, an appropriate DSL data link layerprotocolDSL data link layer protocol is selected from the list 120 thatis supported by both the CPE 110 and the DSLAM 130.

The appropriateness of the DSL data link layer protocolDSL data linklayer protocol to be selected to establish a DSL connection may bedetermined according to certain criterion. Such a criterion may be setup based on application needs. For example, an appropriate DSL data linklayer protocolDSL data link layer protocol may be defined as the firstone in the lust 120 that is supported by both the CPE 110 and the DSLAM130. In the system 100, the identification of such a first matchingprotocol may be initiated on behalf of the CPE 110 with respect to thelist 120. For example, the matching-protocol detection mechanism 150 maydetect a matching protocol by testing, one by one, the DSL data linklayer protocolDSL data link layer protocols recorded in the list 120.

The testing of a matching DSL data link layer protocolDSL data linklayer protocol may be conducted in different fashions. For example, thematching-protocol detection mechanism 150 may detect a matching protocolin a round robin fashion. It may also perform the detection using otherstrategies. For instance, the matching-protocol detection mechanism 150may optimize a protocol list so that the protocol stored in the firstposition (i.e., P[1]) is the best option at the time. In this way, thematching-protocol detection mechanism 150 can always try to match thebest option first. When an existing best option becomes obsolete (dueto, for example, upgrade of DSL service), an emerging best option may bedetected and used to replace the previous best option at, for example,P[1].

FIG. 2 is a high level system architecture of a different embodiment ofthe present invention, in which a matching DSL data link layerprotocolDSL data link layer protocol is detected by a matching-protocoldetection mechanism running on a DSL Access Module (DSLAM). In FIG. 2, asystem configuration 200 comprises a Customer Premise Equipment (CPE)110 that may support multiple protocols, a DSL Access Module (DSLAM)130, a second protocol list 140, representing a plurality of M protocolssupported by the DSLAM 130 and stored in the DSLAM 130, and amatching-protocol detection mechanism 150, running on the DSLAM 130 andaccessing the second protocol list 140.

In the system 200, the matching-protocol detection mechanism 150 mayperform protocol detection in a similar fashion as in system 100 exceptthat the detection is executed within the DSLAM with respect to the listof M protocols supported by the DSLAM 130. With configuration 200, thematching-protocol detection mechanism 150 automatically selects a DSLdata link layer protocolDSL data link layer protocol from the pluralityof M protocols that is supported by both the DSLAM 130 and the CPE 110.

FIG. 3 is a high level system architecture of yet another differentembodiment of the present invention, in which a DSL data link layerprotocolDSL data link layer protocol is detected by a stand-alonematching-protocol detection mechanism connecting to both a CPE and a DSLAccess Module (DSLAM). In FIG. 3, a system configuration 300 comprises aCustomer Premise Equipment (CPE) 110, a first protocol list 120,representing all the protocols supported by the CPE 110 and stored inthe CPE 110, a DSL Access Module (DSLAM) 130, a second protocol list140, representing all the protocols supported by the DSLAM 130 andstored in the DSLAM 130, and a matching-protocol detection mechanism 150connecting to both the CPE 110 and the DSLAM 130 to automatically detecta DSL data link layer protocolDSL data link layer protocol that issupported by both the CPE 110 and the DSLAM 130.

In the system 300, the matching-protocol detection mechanism 150 is astand-alone mechanism and may be configured to function in differentoperating modes. For example, in one operating mode, it may performmatching protocol detection on behalf of the CPE 110. In a differentoperating mode, it may perform the detection on behalf of the DSLAM 130.When it operates on behalf of the CPE 110, it may initiate the matchingprotocol detection based on the first protocol list 120 stored in theCPE 110. When it operates on behalf of the DSLAM 130, it may initiatethe matching protocol detection based on the second protocol list 140stored in the DSLAM 130. The operating mode may be configured accordingto the needs when the matching-protocol detection mechanism 150 isdeployed or may be re-configured when the needs change.

FIG. 4 depicts the internal structure of the matching-protocol detectionmechanism 150 and its relationship with an initiating protocol list 420.In FIG. 4, the matching-protocol detection mechanism 150 comprises atriggering mechanism 430, a matching mechanism 440, an operating modecontrol mechanism 450, a failure processing mechanism 460, and aprotocol activation mechanism 470. The matching mechanism 440 detects amatching protocol based on the initiating protocol list 420.

The initiating protocol list 420 corresponds to either the firstprotocol list 120 or the second protocol list 140 (not both), dependingon the operating mode of the matching-protocol detection mechanism 150(whether it functions on behalf of the CPE 110 or the DSLAM 130). Forexample, when the matching-protocol detection mechanism 150 isconfigured to function on behalf of the CPE 110 (e.g., in the system 100or in the system 300), the first protocol list 120 is the initiatingprotocol list. When the matching-protocol detection mechanism 150 isconfigured to function on behalf of the DSLAM 130 (e.g., in the system200 or in the system 300), the second protocol list 140 is theinitiating protocol list.

The operating mode of the matching-protocol detection mechanism 150 maybe directly related to the configuration of the system (e.g., 100, 200,300). For example, with the configuration 100, since thematching-protocol detection mechanism 150 resides in the CPE 110, it maybe configured (e.g., as a default internal configuration) to operateusing the first protocol list 120 as the initiating protocol list. Withthe configuration 200, since the matching-protocol detection mechanism150 resides in the DSLAM 130, it may be configured (e.g., as a defaultinternal configuration) to operate using the second protocol list 140 asthe initiating protocol list. With the configuration 300, since thematching-protocol detection mechanism 150 stands alone, it may need tobe explicitly configured to use one of the two protocol lists (120 or140) as the initiating protocol list.

The device in which the initiating protocol list is stored is aninitiating device. For example, if the first protocol list 120 is theinitiating protocol list, the CPE 110 is the initiating device. If thesecond protocol list 140 is the initiating protocol list, the DSLAM 130is the initiating device. The initiating protocol list 420 in FIG. 4 isset up by an initialization mechanism 410 of the initiating device.

A protocol list (120 or 140) associated with a device (CPE 110 or DSLAM130) records the protocols that are supported by the device. Such a listmay be updated in different situations. For example, it may be updatedwhenever a new matching protocol is detected. In this case, theprotocols stored in the list may be re-arranged according to a differentorder so that the current matching protocol is always stored as thefirst choice (e.g., to optimize the efficiency of the detection). Inaddition, a protocol list may need to be updated whenever the protocolsthat the device supports change. For example, when a central office isupgraded to support more DSL data link layer protocols, the secondprotocol list 140 in the associated DSLAM 130 may be accordinglyupdated. When a protocol list is updated, the initialization mechanismin the device (CPE or DSLAM) may be invoked to re-initialize thecorresponding protocol list.

In the example embodiment illustrated in FIG. 4, the operating mode ofthe matching-protocol detection mechanism 150 may be configured andcontrolled via the operating mode control mechanism 450. Such internalconfiguration may be executed prior to the deployment of the mechanism150 and may be updated when the needs arise.

In FIG. 4, the matching mechanism 440 (that detects a matching protocol)is activated by the triggering mechanism 430. The triggering mechanism430 may activate the matching mechanism 440 on different conditions. Forexample, when power is up (usually after a power down period) and thecorresponding physical layer DSL connection is re-established, thetriggering mechanism 430 may activate the matching mechanism 440 tore-identify the matching DSL data link layer protocol. In addition, whenthe physical layer connection is being re-activated after a period ofdeactivation (due to, for example, idle cycles or usage limit specifiedin a timer profiles), the matching DSL data link layer protocol may alsoneed to be re-identified.

The matching mechanism 440, upon being activated by the triggeringmechanism 430, performs protocol matching between its initiating deviceand the device on the other end of the DSL connection. For example, fora matching-protocol detection mechanism 150 operating for the CPE 110(i.e., the initiating device is the CPE 110), its matching mechanism 440may identify a matching protocol between the CPE 110 and the DSLAM 130by testing each DSL data link layer protocol recorded in the firstprotocol list 120 (the initiating protocol list) to see whether theDSLAM 130 will respond properly. When a proper response to an initiatedprotocol test is received from the DSLAM 130 at the initiating device, amatch is found.

In a different operating mode, the detection is performed in a reversedirection. For instance, the matching mechanism 440 may detect amatching DSL based on the protocol list 140 (initiating protocol list).In this case, the matching mechanism 440 tests each DSL data link layerprotocol listed in the list 140 and monitors the response from the CPE110. A matching is found when an initiated protocol received a correctresponse from the CPE 110.

When a matching protocol is identified, the protocol activationmechanism 470 is triggered, which may activate the detected matchingprotocol and update the initiating protocol list. When a matchingprotocol is not found, the failure processing mechanism 460 is triggeredthat generates appropriate message or report.

FIG. 5 is an exemplary flowchart for DSL data link layer protocoldetection. An initiating protocol list is first initialized at act 510.The matching protocol detection mechanism 150 is triggered at act 520.Once triggered, the matching protocol detection mechanism 150identifies, at act 530, a matching protocol to be used for establishinga DSL connection between the CPE 110 and the DSLAM 130. If a match isidentified successfully, determined at act 540, the matched protocol isactivated at act 560. A success may also be reported. If the match isnot found, a failure is reported at act 550.

FIG. 6 shows an exemplary flowchart of a process that triggers thematching-protocol detection mechanism 150. In FIG. 6, the trigger isactivated whenever the physical layer connection is established (orre-established). There may be different reasons to establish (orre-establish) a physical layer connection. For example, when the poweris brought back up (after the power is down), the physical layerconnection needs to be re-established. When a physical layer isre-activated (after it is deactivated), the physical layer connectionmay also need to be re-established. That is, whenever a physical layeris reconnected, the matching protocol detection mechanism 150 istriggered so that any change in supporting DSL data link layer protocolsmay be detected accordingly

In FIG. 6, two exemplary paths to establish a physical layer connectionare described. One is the path of power down (which brings down thephysical layer connection) and up. The other is the path of physicallayer connection deactivation and re-activation. A physical layerconnection may be deactivated for different reasons. For example, thecentral office may detect that a DSL connection is idle for a certainperiod of time. It is also possible that the central office maydeactivate a DSL connection according to a usage limit specified in thetimer profile of a DSL service. For example, a usage limit may specify amaximum two-hour continuous usage of a DSL connection.

In FIG. 6, the power is down at act 610 and back up at act 620.Alternatively, the physical layer connection is deactivated at act 630and re-activated at act 640. The physical layer connection isestablished at act 650. Once the physical layer is reconnected, thematching-protocol detection mechanism 150 is triggered at act 660.

FIG. 7 is an exemplary flowchart of a process, in which the protocols inan initiating protocol list 420 are tested in sequence to identify amatching protocol. The total number protocols (K) is first determined,at act 710, to control the total number protocols to be tested. Theindex N, based on which the next protocol being tested is determined, isinitialized to 1 at act 720. The matching mechanism 440 tests each ofthe protocols in the initiating protocol list 420 in sequence startingfrom the top protocol in the list (i.e., stored in p[1]) until a matchis found.

The protocol in the current index position (i.e., p[N]) is tested at act730. If the current protocol is a match, determined at act 740, set, atact 750, the result of the matching process to be “success”. If thecurrent protocol is not a match, examine, at act 760, whether all theprotocols in the initiating protocol list 420 have been tested. If thereare more protocols to be tested, increment the index value N at act 770and return to act 730 to test the next protocol. If all the protocols inthe initiating protocol list 420 have been tested, set the result of thematching process to be “failure” at act 780.

FIG. 8 is an exemplary flowchart for the processing after a matchingprotocol is identified. Assume that the identified matching protocol islisted in location P[N] of the initiating protocol list 420, where N isthe index value of the matching protocol. The existing initiatingprotocol list 420 is optimized, at act 810, through swapping theprotocol stored in the first position of the list (i.e., P[1]) with thematching protocol stored in the current index position (i.e., P[N]). Bydoing so, the first position in the initiating protocol list 420 alwaysstores the current matching protocol. The initiating protocol list 420is then updated at act 820. This may include store the updatedinitiating protocol list 420 in the flash of the initiating device (theCPE 110 or the DSLAM 130). The detected matching protocol is thenactivated at act 830. The successful detection result is reported at act840.

While the invention has been described with reference to the certainillustrated embodiments, the words that have been used herein are wordsof description, rather than words of limitation. Changes may be made,within the purview of the appended claims, without departing from thescope and spirit of the invention in its aspects. Although the inventionhas been described herein with reference to particular structures, acts,and materials, the invention is not to be limited to the particularsdisclosed, but rather extends to all equivalent structures, acts, and,materials, such as are within the scope of the appended claims.

What is claimed is:
 1. A system, comprising: a customer premiseequipment configured to be an initiating device and storing aninitiating protocol list for establishing a DSL connection using atleast one protocol from said initiating protocol list and supported bysaid customer premise equipment, wherein the initiating protocol list isbased on application needs; a digital subscriber line access module forestablishing said DSL connection between said customer premise equipmentand said digital subscriber line access module using a matchingprotocol, said matching protocol comprising said at least one protocoland supported by said digital subscriber line access module; and amatching protocol detection mechanism for detecting said matchingprotocol prior to establishing said DSL connection, wherein saidmatching protocol detection mechanism optimizes said protocol list bystoring said matching protocol at a first place in the initiatingprotocol list to be tested first.
 2. The system according to claim 1,wherein said matching protocol detection mechanism runs on said customerpremise equipment.
 3. A system comprising: a digital subscriber lineaccess module configured to be an initiating device and storing aninitiating protocol list for establishing a DSL connection using atleast one protocol from said initiating protocol list and supported bysaid digital subscriber line access module, wherein the initiatingprotocol list is based on application needs; a customer premiseequipment for establishing said DSL connection between said customerpremise equipment and said digital subscriber line access module using amatching protocol, said matching protocol comprising said at least oneprotocol and supported by said customer premise equipment; and amatching protocol detection mechanism for detecting said matchingprotocol prior to establishing said DSL connection, wherein saidmatching protocol detection mechanism optimizes said protocol list bystoring said matching protocol at a first place in the initiatingprotocol list to be tested first.
 4. The system according to claim 3,wherein said matching protocol detection mechanism runs on said digitalsubscriber line access module.
 5. A system comprising: a customerpremise equipment for establishing a DSL connection using one of a firstset of protocols supported by said customer premise equipment; a digitalsubscriber line access module for establishing said DSL connectionbetween said customer premise equipment and said digital subscriber lineaccess module using a matching protocol that is one of a second set ofprotocols supported by said digital subscriber line access module andthat matches said one of the first set of protocols; and a matchingprotocol detection mechanism for detecting said matching protocol priorto establishing said DSL connection, said matching protocol detectionmechanism to be initialized with an initiating protocol list thatrecords an initiating protocol comprising one of said first set ofprotocols supported by said customer premise equipment or one of saidsecond set of protocols supported by said digital subscriber line accessmodule, wherein the initiating protocol list is based on applicationneeds, and wherein said matching protocol detection mechanism optimizessaid protocol list by storing said matching protocol at a first place inthe initiating protocol list to be tested first.
 6. The system accordingto claim 5, wherein said matching protocol detection mechanism is astand-alone mechanism connecting to both said customer premise equipmentand said digital subscriber line access module and operating in aninternally configurable operating mode.
 7. The system according to claim6, wherein said operating mode includes the mode in which said matchingprotocol detection mechanism functions on behalf of said customerpremise equipment and initiates the detection with respect to the firstset of protocols.
 8. The system according to claim 6, wherein saidoperating mode includes the mode in which said matching protocoldetection mechanism functions on behalf of said digital subscriber lineaccess module and initiates the detection with respect to the second setof protocols.
 9. A matching-protocol detection mechanism, comprising: atriggering mechanism for activating said matching-protocol detectionmechanism according to a criterion; a matching mechanism, connecting toboth a customer premise equipment and a digital subscriber line accessmodule, for identifying a matching protocol supported by and used byboth said customer premise equipment and said digital subscriber lineaccess module to establish a DSL connection based on an initiatingprotocol list, wherein the initiating protocol list is based onapplication needs; a protocol activation mechanism for activating saidmatching protocol after it is identified by said matching mechanism andfor optimizing said initiating protocol list by storing said matchingprotocol at a first place in the initiating protocol list to be testedfirst; and a failure processing mechanism for reporting a failure whensaid matching mechanism fails to detect said matching protocol.
 10. Thematching-protocol detection mechanism according to claim 9, furthercomprising: an operating control mechanism for configuring andcontrolling the operating mode of the matching mechanism.
 11. A methodfor detecting a matching DSL data link layer protocol, comprising:initializing, by a device, an initiating protocol list to record atleast one initiating protocol, wherein the initiating protocol list isbased on application needs; triggering a matching-protocol detectionmechanism based on at least one condition; detecting, via thematching-protocol detection mechanism, a matching protocol from said atleast one initiating protocol, said matching protocol being supportedand used by both a customer premise equipment and a digital subscriberline access module to establish a DSL connection; optimizing saidinitiating protocol list by storing said matching protocol at a firstplace in the initiating protocol list to be tested first; activating,via the matching-protocol detection mechanism, the matching protocol ifthe matching protocol is identified by said detecting; and reporting afailure, via the matching-protocol detection mechanism, if the matchingprotocol is not found by said detecting.
 12. The method according toclaim 11, wherein said at least one condition includes: when thephysical layer connection is established when the power is up; or whenthe physical layer connection is established when the physical layerconnection is activated.
 13. The method according to claim 11, whereinsaid matching protocol includes an Asynchronous Transfer Mode layerconforming to a specification promulgated by the InternationalTelecommunication Union in ITU-T Recommendation I.361.
 14. The methodaccording to claim 11, wherein said matching protocol includes anAsynchronous Transfer Mode conforming to a Frame-based User-NetworkInterface specification promulgated by the ATM Forum TechnicalCommittee.
 15. The method according to claim 11, wherein said matchingprotocol includes High-Level Data Link Control procedures.
 16. Themethod according to claim 11, further comprising: determining, prior tosaid triggering, said at least one initiating protocol supported by adevice that is configured to be the initiating device of saidmatching-protocol detection mechanism; and initializing an initiatingprotocol list that records said at least one initiating protocols. 17.The method according to claim 16, wherein said initiating deviceincludes one of: said customer premise equipment; or said digitalsubscriber line access module.
 18. The method according to claim 17,wherein said detecting said matching protocol is performed according toan order in which said at least one initiating protocol are stored inthe initiating protocol list.
 19. The method according to claim 18,wherein said activating the matching protocol comprises updating theinitiating protocol list stored in the flash of said initiating device;and initiating said matching protocol.
 20. A method for establishing aDSL connection using a matching protocol, comprising: initializing, by adevice, an initiating protocol list to record at least one initiatingprotocol, wherein the initiating protocol list is based on applicationneeds; retrieving, via a matching-protocol detection mechanism, a recordindicating a matching protocol from said initiating protocol listsupported by both a customer premise equipment and a digital subscriberline access module; optimizing said initiating protocol list by storingsaid matching protocol at a first place in the initiating protocol listto be tested first; and establishing a DSL connection between thecustomer premise equipment and the digital subscriber line access moduleusing the matching protocol.
 21. The method according to claim 20,further comprising: detecting, by a matching-protocol detectionmechanism, said matching protocol prior to said retrieving; andgenerating said record that represents said matching protocol.
 22. Anon-transitory computer readable medium having program code recordedthereon, such that when the code is read and executed by a computer, thecomputer is caused to detect a matching DSL data link layer protocol by:initializing an initiating protocol list to record at least oneinitiating protocol, wherein the initiating protocol list is based onapplication needs; triggering a matching-protocol detection mechanismbased on at least one condition; detecting, via the matching-protocoldetection mechanism, a matching protocol from said at least oneinitiating protocol, said matching protocol being supported and used byboth a customer premise equipment and a digital subscriber line accessmodule to establish a DSL connection; optimizing said initiatingprotocol list by storing said matching protocol at a first place in theinitiating protocol list to be tested first; activating, via thematching-protocol detection mechanism, the matching protocol if thematching protocol is identified by said detecting; and reporting afailure, via the matching-protocol detection mechanism, if the matchingprotocol is not found by said detecting.
 23. The non-transitory computerreadable medium according to claim 22, wherein said code recorded on themedium further causes said computer to: determine, prior to saidtriggering, said at least one initiating protocol supported by a devicethat is configured to be the initiating device of said matching-protocoldetection mechanism; and initialize an initiating protocol list thatrecords said at least one initiating protocols.
 24. The non-transitorycomputer readable medium according to claim 22, wherein said activatingthe matching protocol comprises updating the initiating protocol liststored in the flash of said initiating device; and initiating saidmatching protocol.
 25. A non-transitory computer readable medium havingprogram code recorded thereon, such that when said code is read andexecuted by a computer, the computer is caused to establish a DSLconnection using a matching protocol by: initializing an initiatingprotocol list to record at least one initiating protocol, wherein theinitiating protocol list is based on application needs; retrieving, viaa matching-protocol detection mechanism, a record indicating a matchingprotocol from said initiating protocol list supported by both a customerpremise equipment and a digital subscriber line access module;optimizing said initiating protocol list by storing said matchingprotocol at a first place in the initiating protocol list to be testedfirst; and establishing a DSL connection between the customer premiseequipment and the digital subscriber line access module using thematching protocol.
 26. The non-transitory computer readable mediumaccording to claim 25, wherein the code recorded on the medium furthercauses said computer to: detect, by a matching-protocol detectionmechanism, said matching protocol prior to said retrieving; and generatesaid record that represents said matching protocol.